This invention relates to methods of fabricating semiconductor components.
Integrated circuits are typically formed on a semiconductor substrate such as a silicon wafer or another semiconducting material. In general, layers of various materials which are either semiconducting, conducting or insulating are utilized to form the integrated circuits, typically on only one side of the substrate. By way of example, the various materials are doped, deposited and etched using various processes.
Each wafer is processed to include a large number of semiconductor dice or chips. The semiconductor dice are identifiable and spaced from one another by scribe line area or street area. xe2x80x9cScribe line areaxe2x80x9d and xe2x80x9cstreet line areaxe2x80x9d are used synonymously herein, and such are typically areas on the substrate within which no circuitry is fabricated. Alternately by way of example only, such scribe line area might include some circuitry (i.e., test circuitry or burn-in circuitry).
Following circuitry fabrication, the wafer is diced or singulated to separate the individual dice from one another for packaging or for use in an unpackaged form. The present two main techniques for wafer cutting are scribing and sawing. With typical scribing, a diamond tip scribe is moved across the surface of the wafer along the street area. The diamond scribe forms shallow scratches on the wafer surface. Other scribing methods can of course be used, for example scribing with a laser or fluid such as water. Upon the application of pressure to the scribed wafer, such as with a roller, the wafer separates along the scribe lines. The breaks in the wafer typically follow the crystal lattice structure of the wafer substrate. Scribing is typically used for wafers about 10 mils or less in thickness.
For thicker wafers, cutting by sawing is presently the preferred method for dicing, although cutting by scribing can also be used. With one typical type of sawing, a diamond-tipped mechanical saw rotating at high rpms contacts and saws the wafer along the scribe line area. Other techniques can of course be used, for example cutting with a laser or fluid such as water. Regardless, cutting/sawing can be partially or completely through the wafer. Typically, and especially with saw cutting, the wafer is mounted on a supporting member such as an elastomeric adhesive film stretched across a film frame. Upon singulation, the singulated dice remain adhering to the elastomeric adhesive film and are ultimately removed therefrom. Then, the individual dice are typically encapsulated in a suitable protecting plastic polymer film, and wired appropriately.
Recently, fabrication techniques have been proposed and used which provide at least some degree of protective polymer encapsulation of the dice prior to their singulation from the wafer. This is commonly referred to as wafer scale integration or fabrication. Exemplary techniques include the application of the finishing or protecting polymer over the front and back sides of the substrate, then dicing the substrate by cutting through the polymer and substrate. In another method, partial cuts are made into the scribe line area, and then subsequently filled with the protective polymer. When using a mechanical saw, a thinner/narrower saw is then used to cut through the polymer within the previous saw cuts, and through uncut portions of the substrate therebeneath, for singulating the dice from the wafer. In either such events, the mechanical saw cuts through the polymer material which unfortunately can adhere to and foul the saw. This can require considerable undesirable periodic cleaning of the saw blades to achieve the desired dicing effect from wafer to wafer.
The invention was motivated in addressing the above issues and improving upon the above-described drawbacks. However, it is in no way so limited. The invention is only limited by the accompanying claims as literally worded (without interpretative or other limiting reference to the above background art description, remaining portions of the specification or the drawings) and in accordance with the doctrine of equivalents.
The invention includes methods of fabricating semiconductor components. In one implementation, a plurality of semiconductor dice are provided on a substrate having a first side and a second side, with the semiconductor dice being spaced from one another by scribe line area. A stencil is positioned over at least one of the first side and the second side of the substrate. The stencil has masking sections which cover at least portions of the scribe line area. A polymer is applied through the positioned stencil onto the first or second side of the substrate over which the stencil is received, with the stencil substantially precluding the polymer from being applied on the covered portions of the scribe line area. After the applying, portions of the scribe line area are cut into and the plurality of dice are singulated from the substrate.
In one implementation, a method of fabricating semiconductor components includes providing a plurality of semiconductor dice on a substrate having a first side and a second side. The semiconductor dice are spaced from one another by scribe line area. A stencil is positioned over the first side of the substrate. The stencil has masking sections which cover at least portions of the scribe line area. The stencil also has at least one alignment mark. A polymer is applied through the first-side positioned stencil onto the first side of the substrate, with the stencil substantially precluding the polymer from being applied on the covered portions of the scribe line area on the first side. At least one alignment mark is formed on the first side polymer with the at least one stencil alignment mark. After applying the polymer onto the first side of the substrate, the stencil is positioned over the second side of the substrate in a manner that aligns all stencil alignment marks with all first side polymer alignment marks. A polymer is applied through the second-side positioned stencil onto the second side of the substrate, with the stencil substantially precluding the polymer from being applied on the covered portions of the scribe line area on the second side. After applying the polymer onto the second side of the substrate, the stencil is removed from the second side and portions of the scribe line area are cut into and the plurality of dice are singulated from the substrate.
Other aspects and implementations are contemplated.